CCNet 90/2002 - 26 July  2002

"We are in the midst of an orgy of misinformation and confusion in
the press, concerning asteroid 2002 NT7."
--David Morrison, NEO News (07/25/02)

"It's the old train on the track problem," Dr. Donald K. Yeomans of
the Jet Propulsion Laboratory said. "You don't know when the train is
going to arrive at the crossing point.
After 2019, NT7 will have several more close passes by Earth,
including 2044, 2053, 2060 and 2078. Dr. Yeomans said that with a few
more weeks of observations, astronomers will probably be able to rule out
any chance of impact for all of them."
--Kenneth Chang, The New York Times, 25 July 2002

"Thus, [Gareth] Williams notes, the public is likely to see
additional warnings first raised then lowered as search efforts turn
up new asteroids and comets. Though astronomers are concerned about
being seen as "crying wolf," they say they would rather provide initial
information and later ease a warning than face accusations that they
withheld information if an asteroid turns out to have Earth in its
--Peter N. Spotts, The Christian Science Monitor, 26 July

(1) ASTEROID 2002 NT7
    JPL, 24 July 2002

    The Christian Science Monitor, 26 July 2002

    The New York Times, 25 July 2002

    NASA Science News for July 26, 2002

    Xinhua News Agency, 26 July 2002

    The Nation, 26 July 2002

    The Mirror, 25 July 2002

    The Times, 25 July 2002

    Space Daily, 25 July 2002

     The Daily Record, 26 July 2002

     North, 25 July 2002

     David Morrison <>

     Benny Peiser <>

     Jon Giorgini <>

     Kelly Beatty <>

     Charles Cockell <>

     Daniel Fischer <>



     The Sun, 25 July 2002

(1) ASTEROID 2002 NT7

>From JPL, 24 July 2002

Asteroid 2002 NT7 currently heads the list on our IMPACT RISKS Page because
of a low-probability Earth impact prediction for February 1, 2019. While
this prediction is of scientific interest, the probability of impact is not
large enough to warrant public concern.

Discovered on July 9, 2002 by the LINEAR team, asteroid 2002 NT7 is in an
orbit, which is highly inclined with respect to the Earth's orbit about the
sun and in fact nearly intersects the orbit of the Earth. While the orbits
of Earth and 2002 NT7 are close to one another at one point in their
respective orbits, that does not mean that the asteroid and Earth themselves
will get close to one another. Just after an asteroid like 2002 NT7 is
discovered, the limited number of observations available do not allow its
trajectory to be tightly constrained and the object's very uncertain future
motion often allows a very low probability of an Earth impact at some future
date. Just such a low probability impact has been identified for February 1,
2019 and a few subsequent dates. As additional observations of the asteroid
are made in the coming months, and perhaps pre-discovery archival
observations of this object are identified, the asteroid's orbit will become
more tightly constrained and the future motion of the asteroid will become
better defined. By far the most likely scenario is that, with additional
data, the possibility of an Earth impact will be eliminated.

This is an example of the type of scenario that we can expect as some types
of near-Earth objects are discovered. For some objects, their uncertain
initial orbits cannot be used to immediately rule out future very
low-probability Earth impacts, but when additional observations are used to
refine the initial orbit, these low-probability Earth impact possibilities
will go away. Other recently discovered near-Earth asteroids will be added
to the Risk page until their orbits are refined and they are then dropped
off the list of closely watched objects. This is how the system is expected
to work and any initial indication of a low-probability Earth impact
followed by a removal of that event from our IMPACT RISKS tables should not
be considered a mistake. It is a natural result of the on-going process of
monitoring the motions of near-Earth objects.


>From The Christian Science Monitor, 26 July 2002

A new discovery highlights the need to focus worldwide efforts to track
space matter.

By Peter N. Spotts | Staff writer of The Christian Science Monitor

Astronomers worldwide are tracking a mile-wide chunk of space rock to
determine if a close encounter with Earth projected for Feb. 1, 2019 will be
too close for comfort. Their efforts highlight what some scientists see as a
need to focus scattered attempts to deal with threats from asteroids and
comets, which have violently rewritten the history of life on Earth over
billions of years.

On Wednesday, astronomers announced that asteroid 2002 NT7 has a small
probability - less than 1 chance in 200,000 - of striking Earth during its
2019 flyby. Researchers expect this probability to shrink as they make more
observations and use new data to refine calculations of the
asteroid's position and orbit.

The asteroid was discovered July 9 by the LINEAR project, an automated
search for near-earth asteroids conducted by the MIT Lincoln Laboratory in
Lexington, Mass. The asteroid orbits the sun once every 2.4 years;
astronomers say if it struck Earth, it would pack the explosive punch of 1.2
million megatons of TNT.

The asteroid's heft, uncertainties about its position, and the relatively
short time for action if it proves dangerous have won it some of the highest
initial hazard ratings ever for a newly discovered asteroid.

Still, "this object does not worry me in the least," says Gareth Williams,
assistant director of the International Astronomical Union's Minor Planet
Center in Cambridge, Mass. He notes that several times over the past few
years, astronomers have discovered asteroids that first appeared to hold the
potential for a collision with Earth but later proved to pose little or no

Crying 'Asteroid?'

The announcements of such discoveries might seem to be cases of astronomers
crying, "Asteroid!," but Mr. Williams holds the process "is perfectly
normal." As astronomers discover new asteroids, they calculate their orbits
and their potential for impact with Earth. They then rate the object on two
threat-rating systems developed over the past decade. Under both systems,
astronomers see the chance that 2002 NT7 will collide with Earth as
"extremely unlikely," but agree that it deserves close monitoring.

To date, scientists have discovered roughly 500 near-earth asteroids larger
than a kilometer across, but they estimate that there may actually be up to
1,200 of them. Astronomers have placed a high priority on building a new 6.5
meter telescope that could spot hundreds more.

Thus, Williams notes, the public is likely to see additional warnings first
raised then lowered as search efforts turn up new asteroids and comets.
Though astronomers are concerned about being seen as "crying wolf," they say
they would rather provide initial information and later ease a warning than
face accusations that they withheld information if an asteroid turns out to
have Earth in its crosshairs.

Yet if efforts to discover new near-earth asteroids are ramping up, efforts
to prepare for a verified threat are "haphazard" and "unbalanced," says
Clark Chapman, a researcher in the office of space studies at the Southwest
Research Institute in Boulder, Colo. Few policymakers are prepared to
respond to such a warning.

But that may be changing. Earlier this month, representatives from NASA, the
Minor Planet Center, the US Space Command, and others met with House Space
Subcommittee chairman Dana Rohrbacher (R) of California on Capitol Hill to
discuss challenges and opportunities for asteroid-hazard mitigation.

Two approaches often discussed are: using some kind of rocket motor to
deflect the asteroid, or - as a last resort - blowing it up before it
reaches Earth. Dr. Chapman and colleagues Daniel Durda and Robert Gold have
noted that before taking either of those steps, researchers must discover
its composition and other characteristics. They propose placing small
reconnaissance craft on orbit early, to shorten the time between alerts and
scoiting missions. (Currently, it can take 18 to 24 months to launch such a
mission.) Spacecraft designed to deflect or destroy asteroids also could be
set on orbit to shorten response time. The trio estimates that with 30
years' warning, a space shuttle main engine could deflect a
1-kilometer-class asteroid.

For larger objects at shorter notice, explosives may be the only option, but
this technique could lead to Earth's bombardment by asteroid fragments,
which could prove more risky than a single, large impactor. "You can't go
blindly in and nuke the thing as it comes by," Williams says.

Unexpected consequences

Yet large impactors may not be the most serious immediate threat. In June,
when the India-Pakistan crisis was at its height, US early-warning
satellites caught a bright flash over the Mediterranean Sea - a burst that
released enough energy to match the atomic bomb that leveled Hiroshima,
according to Brig. Gen. Simon Worden, deputy director of operations for the
US Space Command. The cause: an asteroid, perhaps five to 10 meters wide.

Had the burst occurred at the same latitude a few hours earlier, "the
results on human affairs might have been much worse," since Pakistan and
India lack the sensors to distinguish between an asteroid and a nuclear

"This situation alone should be sufficient to get the world to take notice
of the threat of asteroid impact," he says.

Copyright 2002, The Christian Science Monitor


>From The New York Times, 25 July 2002


A newly found asteroid, large enough to wreak worldwide destruction, will
cross Earth's path in 2019, and although the chance of a collision is slim,
astronomers cannot yet rule it out.

If the asteroid, named 2002 NT7, were to hit, it would be on Feb. 1, 2019.
The odds of that happening are less than 1 in 200,000, NASA's Jet Propulsion
Laboratory said yesterday. That is roughly the same chance that an unknown,
as yet unseen meteor will hit Earth between now and then. Scientists expect
the 1-in-200,000 odds to grow longer as they learn more about the asteroid's

On the 0-to-10 Torino scale describing asteroid hazards, 2002 NT7 ranks a 1,
meriting careful monitoring but with the chance of impact judged extremely
unlikely. A ranking of 0 means no danger; a 10 means certain impact with
worldwide devastation.

In earlier asteroid scares, astronomers quickly ruled out any chance of
impact, or the potential impact remains so far in the future that it is
impossible to judge the risk.

Astronomers first spotted 2002 NT7 on July 9. With two weeks of
observations, they have mapped out its orbit fairly precisely - it circles
around the Sun once every 837 days at a steep tilt of 42 degrees compared to
the orbits of the planets.

But astronomers have not yet pinned down the asteroid's location, which
means their predictions of where it will be on Feb. 1, 2019, may be off by
tens of millions of miles.

"It's the old train on the track problem," Dr. Donald K. Yeomans of the Jet
Propulsion Laboratory said. "You don't know when the train is going to
arrive at the crossing point."

If NT7, which is one-and-one-quarter miles wide, does strike Earth at 60,000
miles an hour, the impact could gouge a crater many miles wide, destroying
large swaths of the surrounding area.

On average, an asteroid of NT7's size hits Earth every few million years.
The meteor that killed off the dinosaurs 65 million years ago was 6 to 9
miles wide.

After 2019, NT7 will have several more close passes by Earth, including
2044, 2053, 2060 and 2078. Dr. Yeomans said that with a few more weeks of
observations, astronomers will probably be able to rule out any chance of
impact for all of them.

Copyright 2002 The New York Times Company

The International Herald Tribune, 26 July 2002


>From NASA Science News for July 26, 2002

An asteroid with almost no chance of hitting Earth made big headlines this
July 26, 2002: I slid a dollar bill across the counter, and the cashier
handed back a lottery ticket. The odds for winning: 1-in-250,000. A long
shot, but you never know.

Walking out of the store, ticket in hand, I glance at a newspaper. "Tony
Phillips wins the lottery!" the headline declared. Gosh, I thought, that
seems premature ... not to mention weird.

Indeed, it's fiction. For one thing, I never buy lottery tickets. But
mainly, no one would write such a headline based on such slender odds.

Yet that's what happened this week, in real life, to an asteroid.

On July 9, 2002, MIT astronomers discovered 2002 NT7, a 2 km-wide space rock
in a curious orbit. Unlike most asteroids, which circle the Sun in the plane
of the planets, 2002 NT7 follows a path that is tilted 42 degrees. It spends
most of its time far above or below the rest of the solar system. Every 2.29
years, however, the asteroid plunges through the inner solar system not far
from Earth's orbit.

After a week of follow-up observations, researchers did some calculations.
There was a chance, they concluded, that 2002 NT7 might hit our planet on
February 1, 2019. The odds of impact: 1-in-250,000.

"Space Rock 'on Collision Course'," a headline declared days later.
"Asteroid Could Wipe Out a Continent in 2019," another one warned. Really.

"In fact," says Don Yeomans, the manager of NASA's Near-Earth Object Program
at JPL, "the threat is minimal. One-in-250,000 is a very small number."

The odds are not only low, but also uncertain. Yeomans explains: "We've been
tracking 2002 NT7 for a very short time--only 17 days so far," Meanwhile,
the asteroid takes 2.29 years to orbit the Sun. Predictions based on such a
small fraction of an orbit are seldom trustworthy.

It's becoming a familiar routine: Astronomers discover a near-Earth
asteroid. With only meager data at hand, they can't rule out a collision in
the distant future. Headlines trumpet the danger. Finally, the alarm
subsides when more data lead to a better orbit--one that rules out an

"As far as the public is concerned," says Jon Giorgini of JPL's Solar System
Dynamics Group, "it just isn't worth getting worked up about an object with
a couple weeks of data showing a possible Earth encounter many years from
now. Additional measurements will shrink the uncertainty by a large
amount--and Earth will (almost certainly) fall out of the risk zone."

Already this is happening for 2002 NT7. The calculated probability of a
collision with Earth is shrinking as astronomers add new data each day. "I
suspect it will take only a few more weeks (or maybe months) to completely
rule out an impact in 2019," says Yeomans.

Giorgini explains further: "When we calculate an asteroid's position (based
on measurements made at a telescope), the result isn't a single point in
space. Instead, it's a volume of space where the asteroid could be with some
probability. We deal with probabilities, not absolute answers, because the
measurements contain errors." For example, optical data can be corrupted by
twinkling and refraction in Earth's atmosphere. (Radar is better, notes
Giorgini, but no radar data have yet been obtained for 2002 NT7.)

"When you project this initial probability region years into the future, it
naturally expands. For a newly discovered object with only a few days
tracking, the uncertainty region can easily grow to cover a big part of the
inner solar system. Because Earth is in the inner solar system, and can
potentially cut through this volume of smeared out probability, we end up
with finite impact probabilities."

"A finite probability, however, is not really a prediction of impact," he
cautions, "but a statement that one is possible." Of course, many things are
possible. Like the newspaper headline "Tony Phillips wins the Lottery!" But
most of them do not happen.

JPL lists asteroids like 2002 NT7 on their Internet "risk page" not to raise
an alarm, says Yeomans, but to alert astronomers when new discoveries merit
attention. "It's important that we continue tracking these asteroids to
refine their orbits," he says. The more observers, the better.

Above: Astronomer John Rogers captured this image of 2002 NT7, faint and far
away, on July 23, 2002, using a 0.3-meter telescope at the Camarillo

What's an ordinary person to do?

The next time you see a headline "Killer asteroid threatens Earth!" ask
yourself two questions: Have we known about this space rock for more than a
week or so? (If not, check again in a month. It probably won't be considered
a killer then.) And what are the odds of impact?

If you're more likely to win the lottery, there's probably nothing to worry


>From Xinhua News Agency, 26 July 2002

BEIJING, Jul 26, 2002 (Xinhua via COMTEX) -- Leading Chinese astronomers
have said they see "little chance" of an asteroid collision with the earth
in 2019, and refute some of the recent unsupported reports on the issue.

Overseas media recently reported a two-kilometer wide asteroid, dubbed 2002
NT7, could collide with the earth on February 1, 2019.

"Such reports are irresponsible," said Jiang Xiezhu, vice president of
China's National Astronomical Observatories (NAO), in an exclusive interview
with Xinhua.

The asteroid was seen through a New Mexico telescope in the United States on
July 9 by astronomers from the Lincoln Near Earth Asteroid Research Project.

It was then about 135 million kilometers from the earth and was estimated to
be on a 837-day trajectory around the sun, said Jiang.

Doctor Zhu Jin, a NAO researcher, said two weeks of observation was simply
not enough to figure out the asteroid's potential path.

"It needs further observation but poses no threat at the moment, " he said.
"Not until more observation data enables scientists to narrow down its
estimated trajectory can any predictions be made."

Astronomers worldwide have observed 375,000 asteroids since the first was
discovered by Italian astronomers in 1801.

They have worked out the precise trajectories for 44,000 of these asteroids,
none of which is likely to pose any real threat to the earth in the near
future, said Zhu.

Copyright 2002 XINHUA NEWS AGENCY.


>From The Nation, 26 July 2002

Thai astronomers join rush to reassure public that possibility of impact is

Astronomers told Thais yesterday not to panic over reports that a giant
asteroid may hit Earth in 2019 because the chances of a collision are very

Even if the recently discovered asteroid is heading towards Earth a
collision can be prevented, they said.

While it would take relevant agencies several years to work out a
collision-prevention plan, the discovery was made 17 years in advance,
greatly reducing the risk of impact, said Worawit Tanwuttipundit, a member
of the Thai Astronomy Association's board.

Nasa astronomers discovered a two-kilometre-wide asteroid, dubbed 2002 NT7,
on July 9 when it was 135 million kilometres from Earth. Astronomers
forecast the asteroid has a one in 250,000 chance of hitting the Earth on
February 1, 2019. A collision could cause a global catastrophe.

Astronomer Dr Chaiwat Khupatakul said Thais should not be frightened by the
reports. Although the two-kilometre width of the asteroid is considered huge
and could cause a global catastrophe if it hit here, Chaiwat said
astronomers and scientists would be able to invent technologies to prevent
the collision.

Collision could be prevented either by destroying the asteroid with nuclear
or chemical missiles or drawing another asteroid in to hit 2002 NT7, said

There are believed to be millions of asteroids in the region of space
between Mars and Jupiter, although astronomers have only catalogued about
500 of them.

On July 9, astronomers with the Lincoln Near Earth Asteroid Research Project
in the United States discovered the asteroid, which is in orbit around the
Sun, through a New Mexico telescope.

More than 100 follow-up observations allowed astronomers to calculate six
other potential impact dates in 2044, 2053, 2060 and 2078. Were the paths of
2002 NT7 and the Earth to cross, the asteroid would strike the Earth with
the explosive energy of 1.2 million megatons of TNT, according to the Jet
Propulsion Laboratory in the US.

Last month, an asteroid the size of a soccer field missed the Earth by
120,675km in one of the closest known approaches by an object that size.

Sukanya Lim

Copyright 2002, THE NATION, AP 


>From The Mirror, 25 July 2002

WHEN I first brought the subject up in the House of Commons in 1998 it was
met with spiteful laughter. I'm glad to say that the same people are not
laughing any more.

If asteroid 2002 NT7 did hit the Earth it could wipe out a quarter of the
human population.

The chances of something eventually making an impact on Earth are 100 per
cent - we just don't know when it will be.

I have fronted a Parliamentary campaign calling for the government to take
the outer-space threat seriously for the past four years.

Scientific experts have campaigned since the mid-1990s and were inspired by
Arthur C Clarke, considered to be the greatest science fiction writer of all
time, who first coined a phrase "Spaceguard," his fictional early warning
system that detected objects hurtling through space.

Astronomers were concerned about the possibility, but the government was not
taking their concerns seriously.

We are calling for them to do two things. We want a proper tracking campaign
put in place, using a network of six or seven telescopes around the world
that would cover just about every quarter of space. And we need to develop
something to stop an asteroid that's coming our way reaching us. That may
sound like science fiction, but it's actually science fact.

The resources are already available to us. We could use a nuclear weapon, a
rocket or a solar sail to deflect the object. The latter sounds exotic and
has not yet been tested, but it is feasible. A solar sail would use the
constant stream of particles from the sun to cause the asteroid to sail off
in a different direction.

The money needed would be immense - about pounds 80million to track the
objects and another pounds 4,000million to deflect it.

But this is peanuts when you consider that we're talking about Armageddon.

Britain is already ahead of the rest of the world because of the work that
the campaign has done. The Government commissioned a report to see if there
was a threat and confirmed what we had been saying for a long time ... that
there is a danger.

As a result they made 14 recommendations for action, including improvements
on tracking and research.

But now I'm asking the Government to lead international action.

Tony Blair and George W Bush have a special relationship that could be used
here. I would tell him to talk to Bush about an asteroid threat.

And I would ask the Government to give the astronomers the resources to
carry out the necessary research, looking at asteroids and finding out more
about what they are made of.

We must use the next G8 meeting to discuss the issue. It is very serious and
just because it doesn't happen very often, it doesn't mean we should ignore

Tony Blair needs to be a key player. He took a stand against terrorism and
can take a stand about this too.

An asteroid could do much more harm than terrorism can.

Copyright: MGN Ltd


>From The Times, 25 July 2002

By Mark Henderson, Science Correspondent
AN ASTEROID big enough to obliterate Britain and devastate a continent could
be on a collision course with Earth, making it the most threatening object
yet detected in space, scientists said yesterday.

The space rock, 1.25 miles across and named 2002 NT7, will approach our
planet in 2019, and there is a real, though remote, possibility of an impact
that would release almost 750 million times as much energy as the Hiroshima
atomic bomb.

The shock wave from such a strike would cause tsunamis (giant waves) and
fires worldwide as well as a "nuclear winter" effect. It would probably not,
however, be enough to wipe out all life on Earth.

Astronomers say that it is too soon to panic. They have calculated that the
chance of a catastrophe is only 1 in 500,000. But an impact is still 28
times more likely than a player has of winning the Lotto.

The asteroid was discovered on July 5 by the Linear Obervatory in New
Mexico. Its orbit initially suggested an impact on February 1, 2019, but it
now appears that 2002 NT7 will instead pass the Earth at a distance of about
32,000 miles - still a very near miss in cosmic terms.

Iwan Williams, Professor of Astronomy at Queen Mary, University of London,
said: "This is the first that looks even vaguely serious."

The best immediate strategy for dealing with the asteroid would involve
nudging it out of orbit with nuclear weapons
Copyright 2002, The Times


>From Space Daily, 25 July 2002
LONDON (AFP) Jul 25, 2002

A potentially devastating asteroid could strike Earth in 2019, according to
American and British scientists.

Astronomers in New Mexico spotted asteroid 2002 NT7 on July 5. They
calculated that the asteroid, estimated between two and four kilometres in
diameter, had a one in 60,000 chance of hitting Earth on February 1, 2019.

"Today, calculations show a one in 60,000 chance that the asteroid will
strike the Earth," Alan Fitzsimmons, scientist at the National Space Centre
in Leicester, central England, told The Guardian newspaper on Thursday.

A British parliamentary deputy has urged the government not to ignore the

Lembit Opik, from the Liberal Democrats, Britain's third biggest party,
said: "I have said for years that the chances of this asteroid having an
impact which could wipe out most of the human race is 100 percent.

"There's a good chance this particular object won't hit us but we know that
a large object will hit us sooner or later. This is the closest approach we
have seen so far."

The asteroid, travelling at 28 kilometres per second, could cause tidal
waves, massive fires and volcanic activity, added Opik.

Asteroids are often described as the rubble left over from the building of
the solar system.

They orbit the Sun, but the paths are never eternal, and their trajectories
can be deflected by gravitational pull whenever the asteroid passes by a

A football-pitch-sized asteroid capable of razing a major city came within a
whisker of hitting the Earth on June 14.

Asteroid 2002 MN, estimated at up to 120 metres (yards) long, hurtled by the
Earth at a distance of 120,000 kilometers (75,000 miles), well within the
orbit of the Moon and just a hair's breadth in galactic terms.

It is the closest recorded near-miss by any asteroid, with the exception of
a 10-metre (33-feet) rock, 1994 XM1, which approached within 105,000
kilometers on December 9, 1994.

All rights reserved. 2002 Agence France-Presse


>From The Daily Record, 26 July 2002

STARGAZER Patrick Moore took on the role of Dad's Army's Corporal Jones
yesterday to tell worried millions: "Don't panic."

Scientists in the US - like Jonesey's Home Guard comrade Private Frazer -
believe we're "all doomed" because of an asteroid on collision course with
the Earth.

But veteran astronomer Moore says there's very little to worry about,
despite the pessimistic predictions of the world being hit by an
Armageddon-like disaster in 2019.

Scientists in the US say the asteroid, more than a mile wide, will wipe out
a continent if it hits the Earth.

That would cause massive climate change and wipe out life as we know it.

The asteroid, a giant mass of ice and iron known as 2002 NT7, was first
spotted a month ago by astronomers in New Mexico.

Since then, Sky at Night presenter Moore, 79, has been monitoring its
trajectory as it hurtles through space towards our planet.

He said its chances of colliding with Earth were less than of hitting the
lottery jackpot. And even if it is heading straight for us, experts have 17
years to work out how to stop it.

He said: "I have been looking at this projectile for some time and I am
telling everyone don't panic. The chances of this particular asteroid
hitting the Earth are extremely unlikely - you would have a better chance of
winning the lottery.

"Obviously, there is always a chance. But the fact this one has been
detected early means measures can be taken to deflect it with a nuclear
explosion if required."

Moore admits an impact would be devastating, adding: "It would have similar
effects to the asteroid which supposedly wiped out the dinosaurs. Very few
would survive and those that did would have to start again from a second
Stone Age."

Copyright 2002, Daily Record 


>From North, 25 July 2002

Staff Writer

As if the stock market and terrorism weren't enough to worry about this

Astronomers say another newly discovered asteroid, several football fields
wide, will miss the Earth next month - and not by much, astronomically
speaking, at least.

What's more, it has a 1-in-500,000 chance of slamming into us the next time
it's in the neighborhood - 20 years from now.

The asteroid, designated 2002 NY40, was discovered on July 14. It should
sail within 330,000 miles of Earth - just outside the Moon's orbit - on Aug.
17-18, astronomers say.

The hurtling piece of space rock is about 10 times larger than the asteroid
that "narrowly" slipped past Earth - 75,000 miles away, but inside the
Moon's orbit - June 14. That one wasn't noticed until three days later in
astronomers' rear-view mirrors.

Asteroids are pockmarked mini-planets made of rock and iron. Most of them
are orbiting the Sun harmlessly, in a belt between Mars and Jupiter, whipped
around by Jupiter's massive gravity at speeds up to three miles per second.
Others, like this one, follow more eccentric orbits, in some cases crossing
the path of the Earth.

En route, it will appear to hang motionless in the sky - which astronomers
say is the signature of a close-call asteroid, as it bears down on Earth
from deep space.

The new asteroid is nowhere near as large as the killer comets and meteors
that loomed in the recent movies "Armageddon" and "Deep Impact" - or even
the one that threatened Springville on "The Simpsons" TV cartoon.

The asteroid will increase its brightness about 3,000 times during the next
three weeks as it travels here with the northern Milky Way in the background
of the night sky. On the night of Aug. 17 - its closest approach to Earth -
its motion will be visible through binoculars and small telescopes. It will
appear about the size of a star or satellite, moving lazily for a few hours,
high in the southeast sky, on a path that takes it beneath the constellation

"It certainly won't have the beauty or visual thrills of a comet," said
Bruce Draine, a professor of astrophysics at Princeton University and an
astronomer at the observatory there. "Meteor showers are more aesthetically
pleasing. This object will just be a dot of light."

Wayne T. Hally, a meteor expert in High Ridge, agreed. "People are not going
to see a flaming asteroid coming toward them, like you do in the movies,"
said Hally, meteor research coordinator for the New Jersey Astronomical
Association. "It's definitely not a naked-eye event."

The "thrill," if that word applies, of asteroid 2002 NY40 is contemplating
the destruction it would cause if it hit the Earth, Draine said. The
asteroid, which is estimated to be between one-third and one-half mile wide,
would pack the explosive punch of a 50,000- to-100,000-megaton bomb, Draine

"To put it on a scale of badness, it would not be a happy day," he said. "So
an event like that would be catastrophic, especially if it happened with
little or no advance warning.

"The amount of energy released would be much greater than the entire nuclear
arsenals of East and West. Even if it happened in the ocean near populated
areas, it would produce tidal waves that would be devastating disasters," he

An asteroid which is believed to have exploded above Tunguska, Siberia, in
1908, leveling hundreds of acres of trees, was estimated at about 40
megatons, Draine said. If an asteroid that size fell on New York City, "it
would kill millions of people," he said.

Astronomers say that, even with two close encounters in just over a month,
there aren't more rogue asteroids out there. Rather, they are better able
now to detect them.

"We're looking harder,'' Draine said Wednesday. "The telescopes of projects
such as LINEAR in New Mexico and Spacewatch and Arizona are finding things
we would have missed 10 or 50 years ago, things that have been zipping
around the solar system for billions of years."

So, many scientists believe it is "desirable and wise" to have networks of
astronomers surveying the skies and cataloguing as many orbiting objects as
possible, he said. It was LINEAR - the Lincoln Laboratories Near-Earth
Research project in New Mexico - that discovered asteroid 2002 NY40.

"So if there were to be something in the future with the size and impact of
a Tunguska asteroid, we'll know in advance where and when it will happen.
And if we have enough advance warning, we could at least evacuate the area
and take precautions," Draine said. There might even be time, he said, for
nations to unite and blast an incoming asteroid out of the skies, the way
it's done in the movies, he said.

As the asteroid passes the Earth, scientists will be able to better
calculate its orbit and return trip. Tracking agencies, such as NASA's
Near-Earth Object Program, currently put the odds of it hitting Earth on
Aug. 18, 2022 at about 1 in 500,000. This makes a chance of impact
"extremely unlikely, but worrisome just the same," according to the Web site
for Sky & Telescope magazine.

But those odds also mean that "it's 499,999 times as likely that we're not
going to be hit," Hally said. "That's very, very, very, very, very close to
zero," he said.

Copyright 2002 North Jersey Media Group Inc.


>From David Morrison <>

NEO News (07/25/02) Confusion on 2002 NT7

Dear Friends and Students of NEOs:

As you probably all know, we are in the midst of an orgy of misinformation
and confusion in the press, concerning asteroid 2002 NT7.

There have been "false alarm" stories in the past about threatening
asteroids, some originating in poorly informed or misguided statements made
by astronomers. The general pattern has been that a warning is issued and a
day or two later retracted, reflecting either improved calculations or new
data or both. It is entirely normal that a very low probability prediction
of impact will go to zero as more information is processed. This is not a
"failure" of the system, but
rather the normal working of the Spaceguard Survey and supporting dynamical
calculations. However, the press sometimes portrays this as a "mistake" by
astronomers. Consequently, most of us prefer to see no press coverage of
such low-probability predictions. It was in this
spirit that no formal announcement was made concerning 2002 NT7, since new
observations are accumulating and the whole situation is likely to resolve
itself within a few days.

Unfortunately, the media themselves seem to have created the current flood
of publicity surrounding NT7. Initial statements from the British press
stated that 2002 NT7 was on a collision course with Earth with the impact
predicted for February 1, 2019. The only qualification was that the
prediction of an impact was still somewhat uncertain. There was no hint of
the true situation, in which the probability of impact was at the
1-in-a-million level. As noted by Don Yeomans and others, the position of
2002 NT7 on February 1, 2019, is actually uncertain by many millions of

The situation has been made more complex by press references to the Palermo
technical scale for classifying an asteroid risk. Astronomers use this
Palermo scale in communicating among themselves, but several years ago they
agreed to use the simpler Torino risk scale in talking to the press and
public. The Torino scale was invented to facilitate such communication. As
recently noted by Rick Binzel: The largest rationale for the Torino Scale is
that we all have a common lexicon for communicating with the public. If each
and every one of us would say: "That object is only zero (or one) on the
Torino scale, meaning we are carefully monitoring it, with no cause for
public concern." eventually the responsible press and responsible people
would learn to categorize these "events" as being the same as the last ones
that "just went away."

Below are two items: (1) a statement that I am sending to people who e-mail
me expressing their concern that this asteroid will hit in 2019, and (2) a
selection of the distorted initial press coverage in the UK taken from Benny
Peiser's CCNet.

David Morrison


This newly discovered asteroid (2002 NT7) is very unlikely to hit the Earth.
The current odds are a million to one against hitting. In any case,
astronomers are continuing to measure its position, and within a few days we
should know for sure what the circumstances are for 2019. Meanwhile, the
story has been blown out of proportion. Statements from the press that the
asteroid is on a collision course with Earth are simply false.

The probability of impact is so small that this asteroid remains at a risk
level on the Torino scale of 0 or 1 - meaning that the chances of impact
from another unknown NEA of the same size or larger is similar to the
chances of being hit by 2002 NT7. However, the impact probability is not yet
zero, and additional observations are needed to ensure that this object will
not hit the Earth in 17 years.

Although 2002 NT7 is unlikely to pose any danger, the long-term risk of
asteroid collision is real.

The Earth orbits the Sun in a sort of cosmic shooting gallery, subject to
impacts from comets and asteroids. It is only fairly recently that we have
come to appreciate that these impacts by asteroids and comets (often called
Near Earth Objects, or NEOs) pose a significant hazard to life and property.
Although the annual probability of the Earth being struck by a large
asteroid or comet is extremely small, the consequences of such a collision
are so catastrophic that it is prudent to assess the nature of the threat
and prepare to deal with it.

Studies have shown that the risk from cosmic impact increases with the size
of the projectile. The greatest risk is associated with objects large enough
to perturb the Earth's climate on a global scale by injecting large
quantities of dust into the stratosphere. Such an event could depress
temperatures around the globe, leading to massive loss of food crops and
possible breakdown of society. Such global catastrophes are qualitatively
different from other more common hazards that we face (excepting nuclear
war), because of their potential effect on the entire planet and its
population. Various studies have suggested that the minimum mass impacting
body to produce such global consequences is several tens of billions of
tons, resulting in a groundburst explosion with energy in the vicinity of a
million megatons of TNT. The corresponding threshold diameter for NEOs is
between 1 and 2 km. Smaller objects (down to tens of meters diameter) can
cause severe local damage but pose no global threat.

We don't know when the next NEO impact will take place, but we can calculate
the odds. Statistically, the greatest danger is from an NEO with about 1
million megatons energy (roughly 2 km in diameter). On average, one of these
collides with the Earth once or twice per million years, producing a global
catastrophe that would kill a substantial (but unknown) fraction of the
Earth's human population. Reduced to personal terms, this means that you
have about one chance in 20,000 of dying as a result of a collision. Such statistics are
interesting, but they don't tell you, of course, when the next catastrophic
impact will take place-next year or a million years from now.

How much warning will we have? With nearly half of even the larger NEOs
remaining undiscovered, the most likely warning today would be zero -- the
first indication of a collision would be the flash of light and the shaking
of the ground as it hit. In contrast, if the current surveys actually
discover a NEO on a collision course, we would expect many decades of
warning. Any NEO that is going to hit the Earth will swing near our planet
many times before it hits, and it should be discovered by comprehensive sky
searches. This is the purpose of the Spaceguard Survey. In almost all cases,
we will either have a long lead time or none at all.

Meanwhile, the Spaceguard Survey has already discovered more than half of
the near Earth asteroids 1 km or larger, and we are on track to find 90% of
them before the end of this decade.

For more information see the NASA websites: <> and

David Morrison
NASA Ames Research Center


>From Benny Peiser <>

Is the media to blame for "an orgy of misinformation and confusion"
regarding the latest asteroid scare? According to David Morrison's analysis
(NEO News 25/07/02) it would appear that this is the case. After all, impact
risk assessors keep mum this time and "no formal announcement was made
concerning 2002 NT7, since new observations are accumulating and the whole
situation is likely to resolve itself within a few days." So why has
asteroid 2002 NT7 been attracting such phenomenal interest from news outlets
around the globe - and why the often inaccurate reporting?

For a start, it was the first virtual impactor announced by NEODyS to have a
positive rating on the Palermo Scale for a virtual impact this century. "So
what?" It still was rated only as a level 1 NEA on the Torino Scale - and
that's all that counts in asteroid PR. Consequently, we should have
emphasised the Torino Scale message exclusively, says Dave Morrison: "If
each and every one of us would say: "That object is only zero (or one) on
the Torino scale, meaning we are carefully monitoring it, with no cause for
public concern" eventually the responsible press and responsible people
would learn to categorize these "events" as being the same as the last ones
that "just went away."

Sounds convincing - but it isn't. Basically, the misunderstandings about NT7
were mainly due to lingering ambiguities and confusion about the two
different impact risk assessment tools currently used by orbit calculators
at JPL and Pisa University: The Torino Scale
( and the Palermo Scale

As Morrison rightly states: According to the Torino Scale, a virtual
impactor rated as a level 1 object merits "careful monitoring, but no public
concern." Objects rated on this level have impact probabilities below the
yearly background collision probability for objects in this size category.
As far as the Torino Scale is concerned, only close approaches by virtual
impactors that have higher collision chances than the Earth typically
experiences over a few decades "merit concern", i.e. Torino ratings 2 and

The Palermo Technical Scale (,
however, uses quite different terminology:
"Actual scale values less than -2 reflect events for which there are no
likely consequences, while Palermo Scale values between -2 and 0 indicate
situations that merit careful monitoring. Potential impacts with positive
Palermo Scale values will generally indicate situations that merit some
level of concern."

In other words, while a Torino Scale 1 object does not merit public concern,
an object that shows a positive Palermo Scale value "merits some level of
concern." No wonder that most interested observers begin to wonder what to
make of this rather unclear information posted on various impact risk

It should have been obvious to everyone that the (first) discovery of a NEA
with a positive Palermo Scale value for a virtual impact this century would
generate public interest given the cautionary information posted on JPL's
SENTRY website (

"To date, the risks posed by the potential impacts identified by Sentry have
all been well below the background level, and hence, these events have been
of academic or professional interest only, and not deserving of great public
concern. Events with a Palermo Scale value greater than zero are expected to
be very rare, but if one should be predicted, a Technical Review of the
prediction would likely be requested from our colleagues in order to verify
the calculations before the prediction is placed on the Risk Page."

This statement not only calls specific attention to the fact that virtual
impactors with a positive Palermo Scale value are highly unusual ("very
rare"). What is more, it makes clear that if such a NEA were to be detected,
it would warrant the formal involvement of the IAU and "a Technical Review
of the prediction would likely be requested."

Another reason, I guess, why 2002 NT7 attracted more attention that it
deserves (apart from its large size and the relatively short virtual
"warning time") is due to the silence about whether or not such an IAU
Review actually took place. From what David Morrison states, it would appear
that a decision was taken by the IAU and its Review Team not to issue a
press release. I have no  criticism about this decision. In fact, I don't
think an official press release was warranted. Nevertheless, since NT7
presented a 'novel' scenario, and in a way, a 'historic first', it would
have been prudent to added clarifying information to the cryptic data and
calculations on the impact risk pages regarding NT7. (As a matter of fact, I
did ask JPL shortly after their excellent SENTRY programme was launched what
would happen in case a positive Palermo Scale object were to be discovered;
I was told that, in all likelihood, the data would be peer reviewed and
explicatory information posted on the risk pages. I guess that is what many
expected to happen). And indeed, additional information was eventually
provided by JPL on 24 July (, unfortunately only
*after* the story had already hit the various news agencies.

While this lack of expounding information contributed to some uncertainties,
Kelly Beatty, I am pretty sure, was not the only one who seemed confused
about an apparent "significant" difference between the positive Palermo
Scale value announced by NEODyS and the negative PS value published by JPL
(see letter further below).

Given all these technical problems and confusion of our own making (not to
mention the minor confusion about differing impact probabilities, ranging
somewhere from 1:60.000 to 1 in a million), let's not blame the media for a
story poorly "managed" by ourselves. After all, almost all reports written
by some of the most experienced science editors and reporters are based on
the information given to them by more than two dozend of eminent NEO
astronomers and researchers. Instead of blaming the media, let us rather
focus on the unresolved home-made problems so that we can learn some
constructive lessons from the 2002 NT7 events.

So, once again we are forced to address the inherent PR problems of our
handling of the impact hazard in public (whether on impact risk websites,
NEO mailing lists, press interviews or in any other public form). In this
respect, I can find no better way to conclude my brief thoughts than to
quote Brian Marsden's timely caution which he wrote just two weeks ago in
CCNet (12/07/02):

"[The] two groups, at JPL and in Pisa, are routinely carrying out the NEO
impact-probability computations with essentially identical results. If there
were a significant and serious difference, then a review might be in order,
but that is unlikely to happen. In fact, the whole review discussion has
never involved a significant difference in computations from the same data.
The review process need address only what is said, not what is computed. And
what is said should be reviewed, not just by astronomers, but by a group
with expertise also in many other disciplines."
Benny Peiser
26 July 2002


>From Jon Giorgini <>

Dear Benny,

Based on discussions with the press and others in the wake of 2002 NT7, it
seems NONE of the people I have talked to (no one outside the "impact
community") understands the meaning of a listing on a risk page. That is,
the difference between the "potential impacts" and  "predicted impacts".

Two or three weeks of optical data is not enough to conclusively identify an
impact years in the future. POSSIBLE hazards can be flagged, but these are
actually due to the lack of orbit knowledge; the asteroid could be so many
places the Earth can't help but be in some of them.
These listings are POSSIBLE impacts, not PREDICTED impacts.

To PREDICT an asteroid's orbit reliably you need radar measurements or at
least optical observations spanning 1 (preferably two) orbit periods of the
asteroid. With an orbit period of 2.29 years, that means we should be able
to usefully predict 2002 NT7's orbit in a positive way for a few decades
after 2-4 more years of tracking it. By contrast, eliminating an entry on
the risk page is a negative prediction; a prediction of where it will NOT

Results with less data -- 2 or 3 weeks or even months -- are simply
astronomer's doing their routine, daily chore of eliminating obscure

The listings are not really PREDICTIONS of impact, but a statement that one
is POSSIBLE, primarily because it is not known for sure where the asteroid
will be. Of course lots, of things are possible, most of which will not
It's possible I will be on top of Mount Everest next month but I am not
predicting it. And there will come a point when my being on Mount Everest at
some instant can be positively excluded ("that's impossible!").

The purpose behind the risk web page JPL produces is to communicate
possibilities to other astronomers so they know which objects require more
observations. A listing is not a declaration that an object is predicted to
impact, or even come close to the Earth at that time, only that the
possibility has not been ruled out.

As far as the public is concerned, it just isn't worth getting worked up
over an object with a couple weeks of optical data showing a possible Earth
LISTED POSSIBLE IMPACT. A few days later, additional measurements will
shrink the orbit uncertainty region by a relatively large amount and the
Earth will fall out of the risk zone.

A pointer to such objects is valuable to astronomers however, so they
can organize their limited resources to continuing tracking objects with
POSSIBLE (but by no means PREDICTED) impact potential.

In general, it is very difficult for fuzzy optical measurements to narrow
the uncertainties for newly discovered objects. A conclusive impact
detection will almost certainly have to come from radar which can measure
the position of an object to within a few meters. Optical measurements
are typically good only at the 10's-100's of km level which fuzzes out
knowledge quickly in a few years.

The only substantive hazard prediction out there is 1950 DA; 51 years of
optical data and recent radar data together indicate a possible impact event
with odds between 0 and 1-in-300 on March 16, 2880.  Ground-based observers
could track 1950 DA for the next few decades without substantially changing
the possibilities since the orbit uncertainties are so small they are
dominated by the way the asteroid spins in space.


Jon Giorgini                    |Navigation & Mission Design Section
Senior Engineer                 |  Solar System Dynamics Group       |  Jet Propulsion Laboratory


>From Kelly Beatty <>


has anyone besides me noticed that JPL and NeoDYS give significantly
different impact probabilities and, perhaps more to the point, negative and
positive (respectively) Palermo ratings?


MODERATOR'S NOTE: Yes, I also noticed this discepancy. As I understand it,
NEODyS and SENTRY are not identical systems. They use slightly different
assumptions in the error analysis and they sometimes use slightly different
data sets because of the data weighting schemes. Hence,
these minute differences in these uncertainty computations. Although they
*appear* to be significantly different because of their different Palermo
Scale values, the inherent accuracy of the computation programmes at JPL and
Pisa both currently give 2002 NT7 a Palermo Scale of about zero
(background). BJP


>From Charles Cockell <>

Dear Benny,

By co-incidence I am writing to you from the Haughton impact crater in the
arctic, where 23 million years ago a million megaton impact event did occur.

But I'm interested by the article in the Times that makes light of the
impact threat. The chances of a continent-scale devastating impact are low
(perhaps once every 10 million years). The fact that they have occurred is
not in doubt, the fact that they will occur is not in doubt. The fact that
if we don't find a way to stop them we will eventually be doomed is also not
in doubt.

However, it seems to me that the impact community will achieve exactly the
opposite of what it intends if it spits out stories of 'near-misses'. There
are only so many of these that the media will publicise before it gets bored
of the 'impact hazard' as a news item.

Publicising the fact that there are objects out there that could potentially
do devastation if they were on the wrong trajectory is obviously a good
thing and perhaps the best way to inform, but presenting them as
'near-misses', particularly when human civilization has not been virtually
eradicated by them since its birth in Africa approx 3 million years ago is
not going to go unnoticed by the media, hence the Times article.

It seems that to convince people of the need for planetary protection a
strategy of informing people about the vast number of objects and their
possible effects on Earth and the statistical certainty of impact (whatever
that length of time might be) would be better than issuing dire warnings of
near misses.



>From Daniel Fischer <>

Hi Benny,

thanks for keeping us updated with the echoes of 2002 NT7! Some German TV
stations also got crazy about it yesterday, with one reporting that "the
impact probability is only [sic] 10 percent, which does not sound like much
..." The most interesting side aspect of the whole affair was a piece on CNN
International, though, in which science reporter Ann Kellen (sp.?) promoted
solar sails as the best way to deflect a threatening NEA - I wonder where
she got that idea from (as opposed to the more 'popular' stand-off nuclear
weapon concept most everyone else is promoting).

Regards, Daniel



>From, 23 July 2002

By Robert Roy Britt
Senior Science Writer

The continued rapid pace of discovery for large asteroids in relatively
close proximity to Earth suggests there may be more of them than some
scientists have predicted. The speculation, from one of the astronomers who
helps count the rocks, does not imply a significantly increased threat to
Earth, but it does extend a long-running debate over just how many of these
space rocks exist.

Large Near Earth Objects (NEOs) are asteroids bigger than 1 kilometer (0.62
miles) that loosely inhabit the region of the solar system through which
Earth orbits. More than 600 of these large NEOs have been found.

Not a single one is known to be on a collision course with the planet.

However, the big, Sun-orbiting hunks of metal and stone are of great
interest to scientists because of the potential for one being discovered
that could hit us down the road. Such an impact would cause devastation on a
global scale, possibly pushing humans into a Dark Age existence. Experts say
the scenario might be avoided by mounting a mission to deflect or destroy an
asteroid known to be targeting us.

Various research groups from around the world have taken their best shots in
recent years at calculating how many 1-kilometer and larger NEOs are out
there. Estimates have ranged from 700 to 2,000.

Astronomers frequently cite 1,000 as the best estimate these days. Another
popular count, however, is 1,200. Both prognostications are based on
detailed studies and have error margins of plus or minus 100 or 200
potentially deadly giant boulders.

If either of the leading estimates is correct, then just more than half of
all NEOs have been found.

To Brian Marsden, director of the Minor Planet Center where asteroids are
officially catalogued, logic dictates that the pace of discovery ought to be
slowing down, because there are now fewer NEOs that remain to be detected
and hence the chances of finding each one is reduced.

But the pace has not slowed.

"Since the new discoveries are indeed still coming along at about 100 per
year ... the number is probably not 1,000 minus anything, but more likely at
least 1,200 or so," Marsden told

If Marsden is correct, astronomers would not be overly surprised. But his
logic does represent an unexpectedly simple method of suggesting that the
lowball estimates are probably not correct.

Meanwhile, has learned of a new estimate. It comes from NASA
researcher David Morrison and his colleagues and will be presented in a
forthcoming book titled "Asteroids III" (University of Arizona Press).

Morrison, senior scientist at the NASA Astrobiology Institute at the Ames
Research Center, said via e-mail that it's "pretty clear that the number is
not substantially less than 1,000." His team prefers 1,100, plus or minus
100 -- which, Morrison points out, encompasses the possibility of 1,200
suggested by Marsden.

Alan Harris is a co-author of the chapter in "Asteroids III" that deals with
the impact odds. Harris is also researcher at NASA's Jet Propulsion
Laboratory, and he spends a lot of his time making and analyzing these
estimates. Harris said the discovery rate continues to be high in part
because detection methods have improved. It's very difficult to know, he
said, how strong this effect is versus the possibility that there are simply
more asteroids out there than expected.

"A population of 800 is implausible in the light of present discovery rates
and the number already discovered," Harris said. One thousand is plausible,
he added, as is 1,200. "I have to say though that I would be less surprised
if the real population is greater than 1,200 than that if it is less than

Ultimately, the exact number is of little consequence. The important thing
is simply whether or not one of them is headed our way.

Copyright 2002,


>From, 25 July 2002

By Robert Roy Britt
Senior Science Writer

Australian physicist Robert Foot thinks invisible asteroids have bombarded
Earth in the past, unseen comets may be headed our way as you read this. In
fact everything in the cosmos has a mysterious "mirror matter" counterpart,
from stars to planets and even you.

Mainstream scientists are skeptical of the whole theory of mirror matter. It
has been around for decades and is invoked by some to explain "dark matter,"
an unobserved but significant amount of mysterious material that scientists
say must exist based on the effects of gravity they observe in galaxies.

Mirror matter theory holds that for each of the known basic particles, such
as the electron, proton and photon, there is a distinct mirror partner.
Because we are made of ordinary matter, the thinking goes, the mirror
universe and its contents are invisible to us. But mirror matter would have
mass, and so it would interact gravitationally with the observable universe.

A handful of physicists around the world adhere to the idea.

"If mirror matter exists, then there should exist also mirror stars, mirror
planets, even mirror life," says Foot, author of a new book, "Shadowlands:
Quest for Mirror Matter in the Universe" (

Mainstream scientists don't all rule out mirror matter.

"The idea of mirror matter is plausible, and as such it should be looked
into," said MIT researcher John Arabadjis, who studies dark matter.
"However, the evidence that has been used to support the idea that mirror
matter actually exists in large quantities is, I think, very flimsy."

Foot's latest defenses of the theory stretch plausibility beyond what
Arabadjis and other researchers are willing to accept. In a statement issued
this week by the University of Melbourne, where he works, Foot claims that a
longstanding puzzle over "missing" comets could be explained by mirror

Missing comets

For 50 years or so, astronomers have known that most comets come from a
distant region of the solar system called the Oort Cloud. Theory predicts
that more comets should make second trips through the inner solar system
than what astronomers observe. In a recent issue of the journal Science,
researchers said the best explanation is that the comets simply

But Foot has another explanation. He said the missing comets "could simply
be mirror comets with embedded ordinary matter. Once they have passed the
Sun, their ordinary volatile components progressively burn off, leaving an
invisible mirror-matter core. This would explain why so many simply fade

Harold Levison, of the Southwest Research Institute and lead author of the
comet study published in Science, disagrees.

"The only reason I can see for invoking mirror matter here is if we did not
understand what happened to the comets," Levison told "However,
we do. They disintegrate. It has been observed many times."

A photograph of just such an event, released earlier this week, supports
Levison's view.

Exploding asteroids

Foot further claims that an infamous 1908 event in Siberia, an explosion
that flattened thousands of acres of forest but left behind no hard evidence
for the cause, involved mirror matter. All leading asteroid experts believe
this so-called Tunguska event was caused by an asteroid that exploded above
the surface, torn apart by atmospheric friction.

According to Foot, the atmosphere could cause heat to build up within a
mirror asteroid, causing it to explode and making it visible, though no
ordinary matter would be left behind.

He also cites an event reportedly observed in Jordan in April 2001. A ball
of light was said to streak across the sky at low altitude, break in two,
and then slam into a hill. Local astronomers found scorched trees but no

"These events cannot be explained in terms of a space body made of ordinary
matter," Foot said. "If the Jordan space body was made of ordinary matter it
should have lit up a large part of the Middle East. This was not observed."

He goes on to suggest that tons of mirror matter might lie hidden just below
the surface of these sites, waiting to be found. Mirror atoms could be
sorted out in a centrifuge, he says.

Levison doesn't think there are any mysteries to look into in Jordan or

"It is well known and modeled that small, normal, rocky or icy impactors
will disintegrate in the atmosphere before they strike the surface of the
Earth," Levison explained. "These small objects can be moving fast enough
that they cause a huge explosion at high altitudes without leaving a crater.
I really don't think you need to invoke strange physics to understand the
astronomical phenomena described" by Foot.

Until and unless the mystery of dark matter is unraveled, however, mirror
matter theory is not likely to go away. And though it might not be needed to
explain missing comets or mysterious explosions, there could be something to

Physics can be strange, points out Arabadjis, the MIT researcher.

When Paul Dirac used math to predict in the 1920s that basic particles have
associated antiparticles, the idea "was so unbelievable to him that, well,
he refused to believe it at first," Arabadjis said. Later experiments
detected these antiparticles (though most scientists do not believe
antimatter equals or begets mirror matter).

And over the past few years, astronomers have realized that the universe's
expansion is actually accelerating, something Arabadjis calls "a truly
bizarre result" that can't be explained. Exotic "dark energy" has been
proposed as a possible repulsive force behind this mystery.

"To be fair, physics sometimes produces really bizarre answers," Arabadjis

Copyright 2002,


>From The Sun, 25 July 2002

1. Dig yourself a very, very deep hole thousands of feet below the Earth's
surface and build a super shelter. Or simply reinforce the house from Big
Brother 19 with concrete and use that as a bunker.

2. Join the latest amateur attempt to build a space rocket from scratch
-now. At least you have 17 years to tinker with the engine to make sure it
doesn't break down.

3. Tie one end of Jordan's bra to Big Ben and the other to Canary Wharf and
catapult the massive asteroid back where it came from.

4. Start saving for a one-way ticket to a space hotel which will probably be
orbiting the Moon by that time.

5. Try to befriend an Extra Terrestrial - and then do your best to bribe the
friendly alien to shuttle you off the doomed Earth and back to the safety of
its home planet.

6. Find out exactly which continent the asteroid is going to hit -  and make
sure you and your family have not booked your holiday there.

7. Get Manchester United's 29.1 million signing Rio Ferdinand to justify
his out-of-this-world transfer fee - and head it back into space.

8. Book a round-the-world plane ticket and hope you are in the air to avoid
the worst when it hits.

9. Bounce it off the Millennium Dome - with any luck we might menage to get
rid of two disasters in one go.

10. Retrain as an astronaut and hope you are on a mission to a far distant
galaxy when the rock collides with Earth.

Copyright 2002, The Sun

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From David Whitehouse <>

Dear Benny,

Once again, some in CCNet are blaming the media for the 2002 NT7 story.

I have read most of the reports about NT7 and the majority of them have
been accurate in reporting the situation regarding this now famous rock.

Most reports said, quite rightly, that, based on the limited data
available, it had an impact solution in 2019, but that more observations
would almost certainly rule out any collision. I cannot agree that the
vast majority of the reports give "no hint of the true situation," as
one astronomer has commented.

Indeed, the vast majority of reports contain accurate quotes from a
handful of experts, yourself included, placing the situation in the
correct context.

It is true that some outlets have been irresponsible, albeit sometimes
obviously light-heartedly so, but that is life and that happens in all

Scientists should learn from the politicians who have this sort of thing
all the time - it doesn't matter - don't take such reports too
seriously. Besides if you want governments to take this situation more
seriously, and provide more funding, such stories are good, you could
say..ahem...heaven sent. Use them. You should be glad of such coverage.

It is also inevitable in such a story, as indeed in many others, that
some outlets will deliberately take a counter view to the original
reports, especially if they did not cover the story in the first rush.

The fact that NT7 was the first positive Palermo scale event was a news
story and anyone savvy with the media would have recognised it as such
and set about to manage the situation so as to get the best from it, as
they saw it. It strikes me that the Torino scale did not fulfil its
purpose this time.

This is a subject of mixed messages as far as the media are concerned. I
have seen many comments from astronomers and Nasa saying (after they had
criticised the media) that NT7 will not hit us but then adding such
phrases as "ALMOST no chance" and "the impact probability is NOT ZERO"
and "there is a GOOD chance that this particular object won't hit us" -
actual quotes. Journalists can drive a cart and horses between ALMOST
and NOT-ZERO. Ask the politicians about it.



David Whitehouse, Science Editor BBC News Online.



Today's Editorial from The New York Times, 26 July 2002

Thank goodness! Another killer asteroid is on the way, just in time to take
our minds off the stock market and foreign affairs. Asteroids, in fact, are
just about the perfect peril - a lot less scary than a close encounter with
a shark and a lot more reliable than Saddam Hussein.

The latest asteroid menace goes by the uninspiring name 2002 NT7. It was
detected two weeks ago by a surveillance system designed to give early
warning of any errant rocks in our neighborhood. This particular rock is
about 1.2 miles wide and is cruising around the sun in a highly inclined
orbit that comes extremely close at one point to our own planetary orbit.
The Earth will reach that intersection less than 17 years from now, on Feb.
1, 2019. If the asteroid gets there at the same time, it would be analogous
to a train and a car colliding at a grade crossing.

The impact would be nowhere near as awesome as the collision 65 million
years ago that kicked up so much dust it wiped out the dinosaurs. But even
if the asteroid simply dug a very big crater, that is surely enough to
warrant some shivers of anticipation.

Most of the astronomers who comment on these things have been playing down
the likelihood of collision, noting that the asteroid could well be many
millions of miles away when Earth passes the intersection. Some say the
chances of NT7's hitting us are less than one in 200,000, or maybe even one
in a million. But no one can be sure until the rock is watched a bit longer,
allowing more precise calculations of its path.

Meanwhile we are free to worry away at our leisure. It's a lot more fun than
fretting every time Tom Ridge or John Ashcroft warns us that terrorists are
out to do us in, at a time and place unspecified. At least with asteroids,
those who issue the warnings know where the terror rock is and can calculate
where it is headed.

Copyright 2002, The New York Times

CCCMENU CCC for 2002